SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd263207510e0da20793f02cf1485f03bfd7521ad86c86a3805f72e2c7249960e' 
  AND token = 'jwzGR9KVUv0Yx63rf5yvfB8AhoV59czPUTN+4reQcPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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