SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a20024c8cc6bd4539ec7c4e61407efdccff51a09739c52286c9b2035fb7b202' 
  AND token = 'JTWDI3A1ikqieqtEOQvTUhNXjryrBIUhCCJlQUWixbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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