SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '685cc89e785633105299f9b9a3dc680d4d36f9f2e2ca59922684e4c898e4f290' 
  AND token = 'lH/cqKwR1u1va36FDXOLs9na155I9Oe6W9/IO1VDKIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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