SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e6b517d96563aac652cf9c71b3e6d48e91f8ac4982fa597bf0c4963041086f6' 
  AND token = 'cfsoBhjoEyfr4OLw4gmu4RnUhBwsnI/xqyUdEJvcZWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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