SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '178ce57f41ac5a17a39082b1491fa55025db1c2af2b0bc84c3f6afbc1cad6248' 
  AND token = 'GmjKzoYBp+QhMJkbAdlLFlxPEMXNZffMnBroIV0JIQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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