SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '675af2b61e575a7e1df0e45900985a9cc014c6bab05cc432a248b80c004bbd3d' 
  AND token = 'ISKdvYFWfTWexB1G5n8Qul6e1o95+ilGyW9+RZk5zDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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