SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '862961ff871058a47dd08da6dc81f00a4596d7ef698edc12b8cdc66fd8989072' 
  AND token = '2/m1Ou6vjpr3krGssnxcvnY2Ku5Sg2P25d/1uys2t/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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