SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbcfb8da25642a1563f23190bf657f6654d13111ae401abff0934caeb8c48528' 
  AND token = '+rknUxQzExYBzUgX/iiw1SVCx/ca0iAMLUZGEh3gPHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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