SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f1b3b82c1bac9057681a5aabf1fcae050b1e7f0a1a30fee70582031f37a9ab' 
  AND token = 'ubgiwUt9qQpjRFIifI01FfZvRlxzHqUYJvjwklafm64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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