SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '939f42c9632e85af90d185ded2251cc8fe8eba42daf6facbb50e3b13f7ca1697' 
  AND token = 'XWcMAppv1A3Zq1+Ma/a9+onJVgNOfe47UGnKAlk3mNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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