SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7d4064d9e045dec5b773b48404abc2ae8f6fdce911a688c7bcf4828fd3b67d6' 
  AND token = 'UFBwMJXpYnmjJv6MzXji/5ZjH7eLTaaJv/f6mK3QBeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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