SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a922795725408e3317b55bcf52f803220bcf544120668d18a74038c8cac25d69' 
  AND token = '6hYltibMHIfGgvOLOKRGQeXSYfF75FV1HkmApEISH/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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