SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '634b8bfa0d5c3190f773fa75b380baa21fe5fee2e7800112173e2243ea15df55' 
  AND token = 'VjzqIvoxPBgnIMKGJ4Ggw57ohimsAM6/kTHS8WCvWvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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