SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52359bd26b18f4c7f58fce4b5c301adf42c7139d05b40953cc4258271d159b9e' 
  AND token = 'ZCeWlAjeRqvIvg1TckxRqPdwDfGruaOq3ybCQG4CNOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00082

JSON explain

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