SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fdc4818e5e26d789d284968aa0b85c6445b56d401432038eb0cfae2715d6f4c' 
  AND token = 'l+zJeXEtK/wJFjvcxiGO7nz5JjHB9jRP1z2sTdE7zhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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