SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9edaa708526b758c6de10beab951d924718c5abef37a45f6bd56ee8d719ef7a' 
  AND token = 'xvcbPefJTrHyOd36qZwRcpLIlurVUzhgKWywY0gt2LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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