SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ebf7b5d4726f66beadc0ab2430a14a076426c35d0c06ac5adb726d8671932c' 
  AND token = 'xfXmiDF0qkRJwsTUq0jfS6wDGh7IG8p/DLvDzUXp9aI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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