SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9a97565bf7f95b96adef0d59397b357a3436ffd20d85868a7b9fd3d44051c6c' 
  AND token = '26FoaT1sckOeCxzg8Gli3Me8SryxPQlKCnI+VDQL0/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}