SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e84cc16ed5a66a2095b9b89b89743d03fa76c1dbc712bc70e29ddccf5d96b5c3' 
  AND token = '7mgxwDtPizpqPKInXEl7CYExS5BHZyVW3NhBG0Mt1lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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