SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a647a65b10876457f9a652918f922eba67330979165e08528c09170f3c245c' 
  AND token = '+C8XAYtcKti6QD7cm6cBSYoLBE8u61mgSnar7ZIJ414=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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