SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ff427638f70e8998fae6bcc0b2555f2269be5ce36906714975d404e2247af34f' 
  AND token = 'eRlg0bgJxRLBVZWo8W90FekDT/KOLHr5SACSSRGbbjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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