SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acf3447ebcd0fb07864507bc93f47706091dc5e2abf0e1a7967efb20d722072e' 
  AND token = 'zkmN4S6SNGf/+hVYpN6LEHfEW9Bnj7QMBkecscGkPAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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