SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '886dbd225920b6968982c566531d379c5814b0bd800a28ba32ee37511c22b5e6' 
  AND token = 'zObxHZWXbkdLzpPgRCK6S6hjMUEmnOHuI+f5+SU94KM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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