SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00874f6959ac72b5d37853ce6679c4733822fd8d5e93c320a2ac61eaae85e374' 
  AND token = 'I/bQ8BRsndQyOjmw+Zkpdyj5BaG96smg9LyhOW9xjoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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