SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ee38e296b14eedbd284bc94fd38cf441f8c0d52022d09b011c23a512106515c' 
  AND token = 'flWA64fIqVVMtBSuHC5HyQGo60nu588pU1PG7IDTZv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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