SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e547b62531d04a675b13820b790ef47e69634ea5f3b883223b9ac25df33115d7' 
  AND token = 'MPoIJ6ngpjzI+XzRIjQgUenXGqDccgZ1vXPXQ2od3CY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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