SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '123c02064e8828ccc153a9f251c2e36fd38a8b9733737fccff9b0fcff38e5fd1' 
  AND token = 'N7r3WW/PrW+NXCvp1EBOCUEWMIEmHK+MHQmqY8E8tGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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