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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e016c21ac5641b52a3dc875ab0e3e8b649b8a49393a94c0c998abdbeea991e1c' 
  AND token = 'Tmf7yH3+7VpQTFvDgRqP2KlQ3KYS/kQr0rP7+6OjIUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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