SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15983422393d1eff92a0bfd03a17c7aa8d9ed6cfcf014938e4d86fdfe486bc27' 
  AND token = 'QLQbLkP6NatzJYZ4n/s5Ww3BKiYUyFop8gOlgBH56Bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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