SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3af64805726b5b4efb42fecccc28a5ba745b1f4f9835268ec823a58841a2be2' 
  AND token = 'IHx9wUUQi+TUCJ0Tf6+oA0GaOOjdTbiM6R0tJL8kP1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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