SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28cff5da5ddbca6038f8753956c2955495c8cd421668106dde0366f1f20e3fe4' 
  AND token = 'SEYz9RXS75NRah/5csDHeqX9/1EQ4LsZwOAEkI5PTik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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