SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7532531c91781ef0d71d4ef4211df66d783fa30fdfc18aa0f258be11cbbbcf2' 
  AND token = 'nMsbarIaay/hDJjRqpVKdMjUr2IR8HXnL+Kc1Q2dRzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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