SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47787f4539947b75148ea9d91c698fdc597e016a424f052482acdf43e259506f' 
  AND token = 'vV0i0dsn8fN5gwLUySCoYwKqRrzt9GnhIWJwyTbu4V4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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