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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0e3cb7a3bab912f41dd9ad53b16b541da15f5af78342c278acda9a30d31c4b5' 
  AND token = 'Ru6Z+VG2sMRUvNDQQDMVLbnz11UPJ65ib2+2OP+CHwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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