SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '203485476f15b350ca893d0e846343b541ff8f79d718853dc4a491b5d7f75b70' 
  AND token = 'xvkl61ftR47/66LyWIi3pOMDXjyO8NQ10FSaR06MaSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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