SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbf03f536fd420d25acf119efb853dec5c7ae11d7726832a7684239c42589706' 
  AND token = 'KuF4u/2MOzZI6jTWW+1mHrCcHCCYXtfVCUYXTXgTLsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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