SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5df9c399ab36ad5755ccf1181ba0afe7d3a7ef35495b74a1c2ff410a944644fb' 
  AND token = 'shSZXDlsjS6dcUIWaafcevGdwOIeUdaaC41EXarkrOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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