SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae2d90e2dba64b95f6f7349515add8333938141299a4dd7e64fa439c13ff2907' 
  AND token = 'vxuSWkmVpGJvIG3T261oz5RGqmprDr1c0SgOkrbmmqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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