SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7534337fff868bc029895b3992c973caa042cf3a84e8da653394076be9bbdc23' 
  AND token = 'qzN6X+OonEoMrglWqE80fKC5iGXp2+EK4WcM3XEDdU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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