SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a60268107241e0839356982f525607561d6a521192a9072eca451305928d6f2' 
  AND token = '1OazWNBjx3oS9hPhs9+L+1xnGZZgmkEwcDUQsDsFcco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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