SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fc2f48c620e9414bdfeb1374864b21835dad4065ec1faef66385203645f1aff' 
  AND token = 'HKMd2+30n0HENRbiNErCRPqaGFpqBzQGPwN3v5XoKxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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