SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cff1dc5d9ba0916a63b09ec615a1df72de277a6dc15024d6b30e63760d9e97c7' 
  AND token = 'qAECEMdTUOaJpKGKmpF7Pq/kvSLTK8EKYCwORMX/Wx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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