SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f1d451381622442d136abe5ea1e146f2512d7f44882daf98c087ae6e66ce05e' 
  AND token = 'Dkxuzp8ezY1ckxpzCikRxrV+4srsDraGNx61Az98pgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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