SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e87a4cc33441a35ece70b1c0383bc89c47dc5f36c42538d2dfabf776c074a052' 
  AND token = 'ypCfMojD6dtXkCXONZY5mDQuc5WzWJwbmR0ZXPdu6NI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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