SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d1b87b1f601074bad7b8ffb5bd068e2b00d216675db3f363cb72aa3342c6c83' 
  AND token = 'mm0XprLPkmxJNBlg1ZvahUwjwkGLKBUwt24pvuWWjPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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