SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50b75b29c84c710c9a4196837c79a0e23ab9035cf3a6630932964fbe90a01be5' 
  AND token = 'TFdJ6BjYPNadavQCZI4bgVQQ/tbDI8CnwKTcOJFFsNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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