SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1826d038cfde14de402db156f5a7a19364c29532c9c2a804689f28373c6515d9' 
  AND token = 'YXGO8KtMy/3hpn9PCZQR3b2yfwrCo+/MzvtJF2XDPEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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