SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99f70f14a00d963568eeeef983c4a55de96d38b19f7cb63b2c9e9157c59ad070' 
  AND token = 'HdWIE3zK3Ew9CiVGMrIgzTjeO/mcppJYopI+uIyYvkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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