SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3fee39e0b1252fe8ff2230e08c0fea2061f07c96f0ae31e6b91128245d62382' 
  AND token = '824xSB9t9Mjxq+S3mQMayEO/UwtRTAy7QpI8AEiRc5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00701

JSON explain

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