SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0e439032ec98e754fc4a3d9fb314a8b484310f2508de1a1fba8011406796646' 
  AND token = 'uVKvOnrGYcNJ7mT4FILLJmDd8RNfIGkK/oYmKcrpCcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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