SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ec0c3dd31fdafcc82463bfd308cc0add686495a03b6cda5c86d56027a0483df' 
  AND token = 'Z0yFVD9sugrehEf9OJWBPRNwVloltJIgxBEQ+5YVXNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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