SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3250650d53843b1d062279ecdacf627917702edf0135cfce20b114667c7fdce' 
  AND token = 'kVbDAsZjscreMlEnCo/fprt/CR4Piw/MM2TTR8LLlgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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