SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e01b2bf39b084475d881839d1d7490c2f57f2a4b1a42cb8bd5a2d5a6c95761' 
  AND token = 'sMsJgKlwhFipjFKAdPsZu1V09l44VJuZb7NJOrhlyjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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