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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da18d61ab02ba9bb3a7d945f419ce2909a5110b9b8aceffe33ff7cdd40d153b2' 
  AND token = 'hkZpsRTm+un1SNjXdfGvhEMZ7yOxjJ/WUS6+V85jot8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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