SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bc0e85d2ef3257a6254877bfd156c8c2667d67e1970c4c697a2a24adbaae970' 
  AND token = 'XeTuS9PTGgs1jADUKNYHMNYSvrWl12Rj/LX/B+vRDus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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