SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb3691457bdbb77200f58c22b527185ba5e8c6caea0df04af40b757658ae809e' 
  AND token = 'iDNcGZBc1okNiX2nhJnB/vWMuE1qMJbV/piqBXRoojA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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