SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dc6e05b4b102016c2ff34bad07401d8f50dabb50f6feeafd5c24e1c5500fc64' 
  AND token = 'LMUZ7jrjheXDC0HF2mirc1Jp/LR2MNFvnF4RO0RlPJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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