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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae6a2e064d3c1e828c747c6013b827ce6b5e23b6760d1f5fd1e5ef693dd88ef5' 
  AND token = '7LIFIXBy8eiV1DvBn7MZb7x+JfrbUTwcjlEYlXr3ewM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}