SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be8468541c437bc49939bd65ff2143bfed55169da2768667f9ad9c4d7659cd23' 
  AND token = 'IdG/Zy02MJITKYJtlXUHHXzrJ7+JUbaa6dOugZ78PUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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