SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c5618cea032d3bfabc22e92bf219521fa7dae6a4fa4041acde65608b9bffee0' 
  AND token = '58+XJvmsKYZyu23/rTiV5gCPq82cVtc9gCOZIhUwvuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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