SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4376c3c4724be49f4de484d71bb256e61abca1dd0f596ec5cf86eaeef0f83c5c' 
  AND token = 'EKe0KGAB3WhWjhOY2PUTQdvA8CDrCoQotnEi8u78s84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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