SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '129313471b5a8a818048c6bdf58cb91dea7b28cbfad469addd2b43a14a75ac5a' 
  AND token = 'cMPSVT4Cedqvtb+EC5gFo4Q2VnVsA+okYPIFpZF0g7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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