SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4efa8e64a68ab2bd6db8ca31d0dba474eb3a7391834e33efb71050278059711' 
  AND token = 'k9hQOGJQBEem+C8ksHoFY7DBI+Mz/jV3I3zB4ZVVD3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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