SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70042223bf9e9cf36e3e85bd5c6da7086bb66d253a999d1f5b6e1ed72ba43710' 
  AND token = 'vUaygaqu9lKf4Bz7oOBPg90dQSuM883T3Le1uNXlGg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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