SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '375911e2a4eec7a749160142665d752196f63b80d2742303aa8fe82109d027ae' 
  AND token = 'OUYGN6oQzNk7xUy15/GHngd1xYG3AC+Yiocf7uYjjiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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