SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0df9ab95def9d57b38672a1f6ddfb3a938847c2229841b46985cf0025836d447' 
  AND token = 'nZOaYTigry/iy7mQX/OESCeSEdgT6e+BK2O1HPSwnbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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