SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e51e224feaba67fd70626c1144cffbe9de81aa8b549301df525dcc2f7bf7b3d' 
  AND token = 'nltml/j3gpDa4Xy6wCQlEtq6kW4zYNvKzCoUOEvlJmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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