SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80934f686bae384be7c198a407f0350626f9ead5847517902181ed98449ac3a1' 
  AND token = 'I6ns8YYhsuMeIkeZmXaHLSu/uN5a6+dXuAwvBKK6jAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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