SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1f43be2dbd91cb5c9bbd65f6136582c5f4fe9cb94ef4ef898f9e4240bbd0204' 
  AND token = '+FygKHZE8pEf2qH2WiMC9kVJFmpK6CmRIs9PXL0wy3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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