SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adbd4252e07cc02f2efa1282bcc6375824ed931f164c8c140284561d3eb03c20' 
  AND token = '6jTVsrnEMUkTR+nV6QDmBbU/3OmEHZjRdSnFakUvw78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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