SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbeac9a9aac2474a7c916508c1ef5241f1e3efefad78249ba1276bf0c315264b' 
  AND token = '3+DiWKcAZhHwzDrHG2OUTGidMznpGZtSaX0yPyjWBN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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