SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6aeef5397e2b2c2953241bf496c75909c6a35ab9d53b39c3a88b6cd4c8a6b38' 
  AND token = 'RHYSwwc8An8KGeH4qjQ4ysGAQ12yb2euwmgSQMRjUso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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