SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55ac40526a580a205cbc1b7188c85ea1ebdb631dfacf6bb91142017180cae789' 
  AND token = '9jhlKE7yr4NyhHuEib9QLQD6GiavMH3MxFqftFkZHP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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