SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f764058360bb7f71cfb411d399c98a3b34bf528b69ff83606d97bfca58fb028f' 
  AND token = 'nTVHktxTrC33IJvNIBtP+iK6d7nVnXFHliYRhjukJms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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