SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '403eb1eefe5eb2ebda183d8d9c4d1e28a915d6df86ac1de4c94bb29c5ce4a0a0' 
  AND token = 'x0MFFKeNObDhHHDP2fqlFvoNnvqGdOfyebJaQbvpzr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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