SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5527e7640aea29bc041fd737098826a7d9ad983b5061e6e5318ff55c62c2a2b1' 
  AND token = '/+/0JvOq3miMQ+LUVZN90CoOXKi9Ywhfn5lnkNB+gNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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